Impedance-Balancing-based Modulation Strategy for Common-Mode Noise Elimination of CHB Converter

Cascaded H-Bridge (CHB) is a promising approach to achieve high efficiency and high power density for power factor correction (PFC) stage in datacenter. However, the parasitic capacitance residing in the circuit might result in severe common-mode (CM) noise issue. A technique designed to solve the noise issue is proposed in this paper. Inductor in the circuit is split into two parts with the same value, which are placed at the positive and negative terminal of AC source. A unique modulation scheme is also proposed to well match the impedance-balancing technique. With this method, CM noise can be effectively reduced without additional transistors. Experimental prototype has been developed to demonstrate the outstanding performance of the proposed technique.